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利用铁素体测试仪研究了316LN不锈钢在不同加热温度和冷却速度下的铁素体析出规律,试验结果表明,加热温度在1280℃以下无铁素体析出,冷却速度在20℃/h以上,无铁素体析出。基于理化检测并结合热处理工艺试验,分析了316LN不锈钢锻件超声波探伤无底波的原因和改善途径,结果表明,造成锻件超声波探伤无底波的原因是严重的混晶,而通过热处理可以减小晶粒尺寸差距,从而提高超声波可探性。不同固溶温度处理后试样常温、高温力学性能以及晶间腐蚀性能试验结果表明,晶粒度级别在4.0级到1.0级之间变化时,316LN不锈钢的力学性能波动较小,晶间腐蚀性能满足要求。相同固溶温度处理时,热处理次数的变化对晶粒尺寸、力学性能的影响较小,晶间腐蚀性能也满足标准要求。
The ferrite precipitation law of 316LN stainless steel at different heating temperature and cooling rate was studied by ferrite tester. The results showed that the ferrite was precipitated without ferrite at 1280 ℃ and the cooling rate was above 20 ℃ / h, Ferrite-free precipitation. Based on the physical and chemical tests combined with the heat treatment process tests, the reasons for the ultrasonic wave undulation of the 316LN stainless steel forgings and the ways to improve them were analyzed. The results show that the reason of the bottomless wave of the ultrasonic testing of the forgings is severe mixed crystal, while the heat treatment can reduce the crystal Particle size gap, thereby enhancing the soundability of ultrasound. The test results of different temperature and high temperature mechanical properties and intergranular corrosion properties of the sample after solution treatment show that the mechanical properties of 316LN stainless steel fluctuate less when the grain size varies from 4.0 to 1.0, and the intergranular corrosion resistance fulfil requirements. The same solution temperature treatment, the number of changes in the heat treatment on the grain size, mechanical properties of small, intergranular corrosion performance also meet the standard requirements.